The following invention relates to a telescope having provision for injecting an auxiliary image into the focal plane of the telescope and more particularly for modifying a telescope in order to provide a projected image which may be superimposed over the image captured in the telescope's field of view.
In classical Newtonian and Cassegrainian telescopes, there is a shadow in the center of the telescope due to light which is vignetted or obstructed by the telescope's secondary mirror. This spot is a shadow that incoming light causes to fall on the primary mirror of the telescope. It therefore represents an unused portion of the aperture of the telescope.
In the past, systems have been proposed for injecting an image which can be a data image, such as a star map, into the field-of-view of the telescope. This image is injected into the telescope's field-of-view by beam-splitting mirrors, prisms and the like, and the image appears as one which is superimposed over the primary image gathered through the lens of the telescope.
The problem with such systems is that the beam-splitting mirrors or lenses reduce the intensity of the primary image and are complex to construct.
It would be very useful to be able to project data, such as the telescope's current position coordinates, as well as wide-angle graphics of the field-of-view at which the telescope is pointed, into the focal plane for viewing, in order to make the finding of other objects outside the field-of-view of the optical telescope easier.